Sound-reproducing instrument



g'wue'ntot L W ESTERBROOK SOUND REPRODUCING INSTRUMENT Filed June 17, 1924 Nov. 10 1925- Patented Nov. 10,1925.

UNITED STATES PATENT OFFICE.

In W. ISTEBBROOK, OF WASHINGTON, DISTRICT OF COLUMBIA.

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Application filed June 17, 1824. Serial No. 720,685.

To all whom it may concern.-

Be it known that I, LEE W. Es'maanoox, a citizen of the United States, and resident of Washington, in the District of Columbia, have invented certain new and'useful Improvements in- Sound-Reproducing Instruments,'of which the following is aspecificatlon.

My invention relates to improvements in reproducers for radio loud talkers or other sound reproducing devices, and it'consists in the combinations, constructions and arrangements herein described and claimed: I

An object of my invention is to provide a dia hragm for sound reproducing and recor ing instruments by means of which a clear, natural and loud tone is secured and in which disagreeable noises are eliminated.

A further object of my invention is to provide a device in which each sound is reproduced distinctly according to its tone valuewhen in combination with numerous other sounds.

A further object of my invention is to use a combination of materials hitherto not used in a diaphragm for sound recording-and reproducing instruments.

Other objects and advantages will appear in the following specification and drawings and the novel features of the invention will be pointed out in the appended claims.

In the accom anying' drawings:

Fig. 1 is a p an view of one form P s Figs. '2, 3, 4, 5 and 6 are-plan views of modified forms of this diaphragm.

Fig. 7 is a cross-section on the line aa of Fig. 1. l

Fig. 8 is a cross-section on the same line a-a of Fig..1showing corrugations used in place of strips. Thesecorrugations separate the diaphragm into sections havingdifl'erent periods of vibration in a similar manner as the strips.

My invention herewith described consists of a diaphragm for. use in sound recording and re roducing instruments of some suitable su stance such as phenol condensation product or silicon steel to a face of which are attached short ribs or strips of a stiff but-bendable material. The obiect of these strips is to divide the diaphragm into "sectime of various size and flexibility, each sectier: having its'own natural period of vibration. The various sections will respond to impulses of their own frequency and comcom anying drawings.

' bine to reproduce the full natural tones impressed upon them without distortion orconfusion.

' In Fig. 1 isshown a form of diaphragm in which the strips bb are narrow and of varied length and width. The group of these members isarranged in a general oblong form each being firmly held to one face of the diaphragm. In Fig. 2 is shown a diaphragm in which the strips are of nearly equal width, arranged in a circular form and connected by means of narrow strips from the same piece of material. Fig. 3 is a modified form of diaphragm in which the strips are allof difierent lengths connected by narrow parts of the same piece of material. Fig. 4 is. a modified form of diaphragm in which narrow stripsare arranged from the center outward in the form of a pyramid and inverted pyramid. Fig. 5 is amodified form of diaphragm in which the members are'curved. Fig. 6 is a. modified form of diaphragm in which the disk has five sides and a group of strips is arranged parallel with each side. In all of these diaphragms the stri s are arranged to form graded scales, t at is The longest, strip in each group lies next to one shorter than itself. The variance in length continues regularly in this manner from the longest strip in each group to the shortest in the same group so of diathat the ends of the strips in each scale to a straight line or a curve asshown in the acere are two principal methods which can be used in the construction of'a diaphragm intended to act in relation with a magnet or magnets. According to one method a disk is cut from a sheet of suitable magnetic material of proper size and shape to fit the housing of a loud talker unit. A number of strips of fibrous material impregnated with a phenol condensation product are cemented on a face of the disk as shown in Figure-1. I prefer to out these strips of an inch wide except the center one which I make wide. For difierent eflects I use other wi ths. I cut the strips from V to 1 inches in length for a diaphragm of 2% inches in diameter, varying these lengths when different results are desired. This method may be used with all of the forms of diaphragms shown in the drawings and described in the specification.

When diaphragms are constructed according to Figs. 4, 5 and 6 they function better if each' group of sisting of flexible strips of varying length arranged at equal distances each from its nearest neighbor on one face of the diaphragm and closely attached thereto.

2. A diaphragm. for sound reproducing or recording instrument comprising a small sheet of resilient, magnetic material. and members consisting of strips of different material and varying area arranged a ingroup form in such a manner that they form regularly graded scales closely attached thereto.

3. A diaphragm for sound reproducing'or recording instruments comprising a disk of resilient material and members consisting of narrow strips of varying lengths and of different material from the disk arran ed in consisting of narrow strips of varyi lengths arranged in the form: of grade scales closely attached thereto.

resilient, magnetic material and members I 5. A diaphragm for sound reproducing or recording instruments comprising a disk of resilient, magnetic material and members consisting of. attached strips of varyin" lengths in group form so arranged that each group forms a regularly graded scale.

In testimony whereof I aflix my signature.

LEE W. Es'rERBaooK. 

